This invention relates to improvements in a rotating frame animal trap. More particularly, the present invention relates to improvements in the frame design of the rotating frame type of trap. By a rotating frame animal trap is meant a trap which comprises a pair of similar frames pivotally connected at adjacent ends for relative rotation on a common axis so as to form by their sides two pairs of co-acting jaws. Heretofore these frames have been substantially square or rectangular in shape, as described in my U.S. Pat. No. 3,010,245, dated Nov. 28, 1961, or part-trapezoidal in shape as described in my U.S. Pat. No. 3,760,531, dated Sept. 25, 1973. At least one actuator, consisting of a coil spring having arms terminating in rings slidable along and encircling one set of adjacent ends of the frames, is used to urge the jaws toward and maintain them in closed position. In my U.S. Pat. No. 3,010,245, such a rotating frame trap is described in which the ends which cooperate with the rings are shaped so that in the set position of the trap, outer portions of these ends on each side of central portions lie substantially parallel to each other, while the central portions of these ends near the common axis of the frames form a cross with each other within the rings on the arms of the coil spring. In this version of trap, the jaw-forming sides of each of the frames lie in a common plane, and the outer portions of the ends extend directly to the jaws. A trigger and release mechanism (for example, as described in the earlier of my above-mentioned United States patents, in Lehn, U.S. Pat. No. 2,947,107, dated Aug. 2, 1960, my U.S. Pat. No. 3,762,094, dated Oct. 2, 1973, maintains the frames in open position when the trap is set, but when the trap is sprung, releases the frames so as to permit, as a result of the action of the actuator rings on the frame ends, rapid rotation of the frames through an angle of about 90 degrees, so that the jaws quickly strike and squeeze an animal in the trap to kill it.
This type of trap is at the present time the most widely available trap based on humane principals in use in North America. It has been favoured by many humane trapping groups because it constitutes a substantial improvement over such traps as the leg-hold trap. However, despite the present wide usage of the rotating frame trap and its humane effectiveness, there is a constant demand from humane trapping groups to improve the humane efficiency of the trap, i.e. to make it more effective so that it kills any desired animal passing through it and so that such animal, when caught by the trap, will be killed as quickly as possible. Depending upon the position of the animal when it is struck by the jaws of the trap which is closing, this trap may kill the animal instantly or quickly, or act simply as a body-holding trap, the length of time for the animal to be killed in this latter instance being indefinite.
One of the difficulties, particularly when larger sizes of such traps are used, or when the actuator rings are larger, is that the jaws of the trap may not be clamped tightly enough together when the trap is in closed position with the actuator rings in fully expanded position at the ends of their "runs" along adjacent frame ends. Unless an animal caught in such a trap is killed instantly by the impact of the jaws on its body, the trap may then act as a body-holding trap and consequently death may be extremely slow. It can be thus readily appreciated that any improvement in these traps which can increase the clamping force of or reduce the distance between co-acting jaws of the trap when in closed position will improve the humane effectiveness of the trap.
The trigger described in my co-pending U.S. Pat. application Ser. No. 479,082, filed June 13, 1974, now abandoned, is intended to increase the chances that an animal will be in a vulnerable position when it is struck by the jaws of the trap, to ensure that more such animals are killed instantly. Similarly, the actuator rings described in my co-pending U.S. Pat. application Ser. No. 498,239, filed Aug. 16, 1974, now U.S. Pat. No. 3,924,347, issued Dec. 9, 1975 act to increase the starting power of the trap as it begins to close on an animal, and to increase the squeezing power of the jaws of the closed trap on an animal caught therein. Both of these features thus constitute important advances in the direction of increasing the humane efficiency of these traps.
It is an object of the present invention to provide an improved frame for such a rotating frame animal trap, in which the jaw-forming sides of each frame lie in a common plane, which can be used with or without these aforementioned features to increase still further the humane efficiency of such traps. It is a further object of the invention to provide an economical improvement which can be made to the rotating frame animal trap which will kill more animals instantly or result in the animal's death or unconsciousness within a shorter period of time.